Recording medium, information recording and reproducing method, and recording and reproducing apparatus

ABSTRACT

Conventionally, as in the case of switching between a DVD-R and a DVD-RAM, when the method of record mark arrangement in a track is changed, the physical format of the disk is also changed. This makes it difficult to ensure compatibility between pieces of data recorded by a plurality of different methods of record mark arrangement. According to the present invention, sector address data and block address data are recorded in each sector by using wobbling or deformation of a recording groove. Then, depending on which address is used, sector data structure is modified, thereby making it possible to select an address data detection and a data structure on a disk in a single physical format depending on the purpose.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information recording medium and aninformation recording and reproducing apparatus that allow recording ofinformation by irradiation with an energy beam. The present inventionrelates particularly to an information recording medium that realizes aplurality of methods of record mark arrangement on a substrate in asingle format and an information recording and reproducing apparatusthat realizes the plurality of methods of record mark arrangement.

2. Related Arts

Information recording and reproducing apparatus heretofore well knowninclude the following two types of apparatus: first, the “DVDSpecifications for Rewritable Disc (DVD-RAM) Part 1 PHYSICALSPECIFICATIONS version 1.0” (November 1998) (hereinafter referred to asan article 1 (DVD-RAM)) and second, the “DVD Specifications forRecordable Disc (DVD-R) Part 1 PHYSICAL SPECIFICATIONS version 1.0”(September 1999) (hereinafter referred to as an article 2 (DVD-R)).DVD-RAM stands for Digital Video Random Access Memory, while DVD-Rstands for Digital Video Disc-Recordable.

Sector structure of the article 1 (DVD-RAM) has the followingcharacteristics. A sector of the article 1 (DVD-RAM) has a sectorstructure with a prepit ID, and a land and a groove forming a recordingtrack meander (wobble). In addition, the sector structure employs anintegrated address system in which address information of the sector isdisposed at the head of the sector as a prepit. The integrated addressis followed by a data field for storing user data; a buffer, a guard,and a VFO field situated before the data field; and a guard and a buffersituated after the data field. Incidentally, a prepit integrated addressof DVD-RAM is referred to as a CAPA (Complimentary Allocated PrepitAddress).

Sector-structure of the article 2 (DVD-R) has the followingcharacteristics. A groove that forms a recording track of a sector ofthe article 2 (DVD-R) meanders (wobbles), and land prepits areperiodically disposed in a land. According to the method of the article2, the period of wobbling is accurately detected by a groove wobblingsignal and a land prepit detection signal, and then timing in recordingis determined with reference to the period of wobbling. As for addressinformation, an address of a single ECC block is distributed over 16sectors, and is recorded as a prepit in a land prepit of each of thesectors within the single ECC block.

According to the typical methods described above, a self-oscillatorcorrects the phase of a recording clock by detecting a wobbling signal,or a recording clock is generated by frequency conversion of thewobbling signal. Thus, a recording clock dependent on the wobblingsignal is generated in some cases.

According to the conventional information recording media andinformation recording and reproducing methods, when the method of recordmark arrangement in a track is changed, the physical format of the diskis also changed, as in the case of switching between a DVD-R and aDVD-RAM, for example. This makes it difficult to ensure compatibilitybetween pieces of data recorded by a plurality of different methods ofrecord mark arrangement.

Specifically, the DVD-RAM has the CAPA, and therefore user data is notprovided in a physically continuous arrangement, while the DVD-R hasphysically continuous user data, as in the case of the DVD-ROM.Therefore, the different methods of record mark arrangement make itimpossible to record information on a DVD-RAM medium by the sameprocedure as that of the DVD-R, for example, and thus make it difficultto ensure compatibility of recorded data.

Moreover, in the examples described above, since frequency of thewobbling detection signal is considerably lower than that of therecording clock, a slight detection error in the wobbling detectionsignal results in significant errors in the frequency and phase of therecording clock. When such a recording clock is used in recording,record marks to be written are not necessarily written reliably atspecified positions on the disk. Therefore, in the case of DVD-RAM, inorder to allow for such errors in the recording clock, length of arecording area within a sector is made somewhat longer than that of arecording area actually used for recording, thereby somewhat decreasingits recording density. In the case of DVD-R, data becomes discontinuousat a linking portion, and thereby a linking loss is caused.

SUMMARY OF THE INVENTION

The present invention relates to an information recording medium thatrealizes a plurality of methods of record mark arrangement on asubstrate in a single format and an information recording andreproducing apparatus that realizes the plurality of methods of recordmark arrangement, by providing a certain degree of freedom toarrangement and structure of a record mark row within a sector. It is aconcept of the present invention to distribute physical addresses(sector address and block address) and thereby set a pre-format. Then,depending on which address is used, sector data structure is modified,thereby making it possible to select an address data detection and adata structure on a disk in a single physical format depending on thepurpose.

More specifically, according to a recording and reproducing method ofthe present invention, a first physical address (a sector address or ablock address) is reproduced, and a second physical address (a sectoraddress or a block address) is not reproduced.

Fundamental concepts of main aspects of the present invention will bedescribed in the following.

According to a first aspect of the present invention, the followinginformation recording medium is provided.

An information recording medium for recording information by irradiatinga recording track on the recording medium with an energy beam andthereby forming a record mark comprises a sector address included in aunit sector of the recording medium; and a block address which indicatesa given address of a given block formed by a plurality of sectors bycombining address information included in the individual sectors.

A typical example of an information retaining portion that retains eachpiece of information forming the above addresses is wobbling ordeformation of a track. A recording member based on this typical examplemay be described as follows. According to a typical aspect of thepresent invention, there is provided an information recording medium forrecording information by irradiating a recording track on the recordingmedium with an energy beam and thereby forming a record mark, whereinthe recording track has wobbling or deformation with a predeterminedperiod, the wobbling or the deformation of the recording track within aunit sector being divided in a temporal direction into a plurality ofportions; at least one of the plurality of divided portions of thewobbling or the deformation of the recording track within the unitsector includes address information of a block address; and at leastanother portion of the plurality of divided portions of the wobbling orthe deformation of the recording track within the unit sector includesaddress information of a sector address.

The wobbling or the deformation of a track is used as an example forlater description of concrete structure of a recording medium accordingto the present invention. However, it is to be understood that theessence of the present invention is not limited to the concretestructure.

The wobbling or the deformation of a track on a recording mediumpreforms information for addressing by a block unit rather than by asector unit and information on an address to be recorded in each sector.A format of the former for addressing by a block unit as described aboveis generally referred to as distributed addressing, because the addressis distributed over the block as a unit and thus recorded. A format ofthe latter is generally referred to as integrated addressing, becauseaddress information is recorded in each sector, mostly at the head ofthe sector. Either of the plurality of addressing methods mentionedabove is selected, and user information is recorded on the recordingmedium according to the format of first recording information and theformat of second recording information. It is to be understood that theaddress information mentioned above includes information on sectorstructure of the sector. User information to be recorded includesinformation that specifies which of the addressing methods describedabove should be used. More specifically, user information includesinformation indicating that address information is to be extracted froman SAF area or to be extracted from an HAF area in each sector, as willbe described later.

Such selection is made typically for the following reasons. The formatfor addressing by a block unit is suitable as a recording format forcurrent DVD-RW mode, because redundancy of address information recordingis at a high level, and therefore few errors will occur in addressinformation. On the other hand, the format in which an address isrecorded in each sector is suitable as a recording format for currentDVD-RAM mode, because its rate of occurrence of address informationerrors is not better than the former, but its information recordingdensity per unit recording length is higher.

Thus, with the recording medium according to the present invention, itis possible to preform fundamental address information in wobbling ordeformation of a recording track, and to select a recording formatsuitable for information to be recorded by the user from the recordingformats for the plurality of modes mentioned above according tocharacteristics of the information to be recorded.

According to a second aspect of the present invention, the followinginformation recording and reproducing apparatus is provided.

An information recording and reproducing apparatus comprises a signaldetecting circuit for converting a period of a configuration of eachrecord retaining portion on a recording track into an electric signal,the recording track being provided in advance on a recording medium andincluding the record retaining portion having the configuration with thepredetermined period; a block address detecting circuit for detecting ablock address by converting a period of the electric signal obtained bythe signal detecting circuit; a sector address detecting circuit fordetecting a sector address by converting the period of the electricsignal obtained by the signal detecting circuit; and an addressswitching circuit for switching between output of the block addressdetecting circuit and output of the sector address detecting circuit andthereby transmitting a resulting output to a controller.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of fundamental structure of a recordingmedium according to the present invention;

FIG. 2 is a plan view of assistance in explaining wobbling;

FIG. 3 is a plan view of an example of a deformed recording groove;

FIGS. 4(a) and 4(b) are plan views of assistance in explaining theentire structure of a disk;

FIGS. 5(a), 5(b), and 5(c) are diagrams for illustrating structure ofrecorded information in a sector on a recording medium;

FIG. 6 is a diagram for illustrating a method of modulation for addressinformation;

FIG. 7 is a diagram showing a relation between periods and frequency ofwobbling obtained by the modulation method of FIG. 6;

FIG. 8 is a diagram for illustrating an address information modulationmethod different from that of FIG. 6;

FIGS. 9(a) and 9(b) each show a relation between periods and frequencyof wobbling obtained by the modulation method of FIG. 8;

FIGS. 10(a) and 10(b) are diagrams of assistance in explaining a methodof reproducing a block address;

FIGS. 11(a) and 11(b) show a relation between a sector structure andinformation to be recorded;

FIGS. 12(a) and 12(b) show a relation different from that of FIGS. 11(a)and 11(b) between a sector structure and information to be recorded; and

FIG. 13 is a block diagram of an information recording and reproducingapparatus according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention will hereinafter bedescribed in detail.

FIGS. 1 to 3 show examples of physical structure of a recording mediumthat forms a basis for the present invention. FIG. 1 is a perspectiveview of a typical example of a recording medium according to the presentinvention. FIG. 1 shows a structure of a recording layer in a regionincluding tracks for recording information. FIG. 2 is a plan view ofassistance in explaining wobbling, and FIG. 3 is a plan view of anexample of a deformed recording groove. FIGS. 4(a) and 4(b) are planviews of assistance in explaining structure of the entire recordingmedium. FIGS. 5 to 12 each show an embodiment of an informationrecording medium. FIGS. 5(a), 5(b), and 5(c) are diagrams of assistancein explaining a sector structure. FIGS. 6 to 9 are diagrams ofassistance in explaining an address information modulating method. FIGS.10(a) and 10(b) are diagrams of assistance in explaining a blockstructure. FIGS. 11(a) and 11(b) show a relation between a sectorstructure and information to be recorded when a block address is used.FIGS. 12(a) and 12(b) show a relation between a sector structure andinformation to be recorded when a sector address is used.

<Physical Structure of Recording Medium>

First, physical structure of an ordinary disk will be briefly described,and then features of a recording medium according to the presentinvention will be described in detail. As illustrated in FIG. 1, arecording member 0 is formed with a metal deposition layer 6 and a dyelayer, for example, as a recording layer 5 on a substrate 1. Aninformation-writable groove track 2 and a land track 3 are formed on thefilm record carrier 5. The land track 3 is adjacent to the groove track2, and plays a role of guiding an energy beam serving as light forreading and recording (writing) of the groove track 2, for example alaser beam 8. The groove track 2 is of a concave shape as viewed in atraveling direction of the laser beam 8, and the land track 3 is of aconvex shape as viewed in the same direction. Generally, the metaldeposition layer 6 is formed as a light reflection plane useful inreflecting the laser beam 8.

The groove track 2 is provided with so-called wobbling, and therebywinds so as to form a wave in a direction parallel to the flat surfaceof the disk at a given frequency. This wobbling allows rotation of thedisk to be controlled during the reading of information. The land track3 is provided with a prepit 4 that indicates recording controlinformation such as address information indicating a recording positionand timing control information for controlling the timing of recording.The groove track 2, the land track 3, wobbling or groove deformationprovided to the groove track 2 and the land track 3, and the prepit 4are formed during production of the disk. During recording ofinformation on the recording medium having such a structure, the opticalbeam 8 is applied such that the center of the optical beam 8 coincideswith the center of the groove track 2. Then, pits that correspond to theinformation are formed on the groove track 2. The dimensions of theoptical beam 8 are set such that when the groove track 2 is irradiatedwith the optical beam 8, the land track 3 is also irradiated with partof the optical beam 8. Reference numeral 9 indicates an optical regionformed by such irradiation. A signal based on the wobbling mentionedabove is detected by using light reflected from the land track 3, and onthe basis of the signal, rotation of the disk is controlled.

FIG. 2 is a plan view of a state of the wobbling as viewed from above. Aregion for pre-format signal recording in a guide groove formed by aland section 10 and a groove section 11 meanders (wobbles) in a planealong the tracks. The groove section 11 has a prepit 4 for pre-formatsignal recording, which is formed by leaving an ungrooved section.

“Recording track deformation” as an alternative to wobbling is realizedby a method as illustrated in FIG. 3, for example. FIG. 3 is a schematicdiagram of a deformed groove as viewed from its top surface. A landsection 13 and a groove section 14 are alternately arranged, andaccording to this method, width of the groove of the groove section 14or the land section 13 is changed. Then, as in the case of wobbling, apre-format signal mentioned above is formed by a signal obtained fromreflected light of the optical beam 8 applied from above the groovesection 14 or the land section 13. In this case, for example,photodetectors PD1 and PD2 are arranged for both sides of the groove toreceive light reflected from their respective sides. On the basis of areflected light signal that corresponds to the deformation of thegroove, address reproduction or control can be effected. Thus, thesignal system can be handled basically in the same manner as in the caseof wobbling. Hence, the following description will be made by takingwobbling as an example, and description for the recording trackdeformation will be omitted.

A relation between various information to be recorded and physicalformat will be described in the following. FIGS. 4(a) and 4(b) are planviews of assistance in explaining structure of the entire recordingmedium. FIG. 4(a) is a plan view of a circular recording medium. FIG.4(b) is a layout of sectors in the proximity of a zone boundary. In thiscase, it is assumed that the recording medium is a disk, and the disk isrotated. A clamping hole 40 for clamping the disk is created in theinnermost portion of the disk.

Around the periphery of the clamping hole 40, there is a read-in area 41where physical conditions of the disk and the like are recorded. Byreproducing information in this disk region, an information reproducingapparatus can obtain various information indicating conditions forrecording various desired information, such as reproducing powerappropriate for reproduction, sector structure, defect information, andoptimum conditions in recording. On the basis of the information, theinformation reproducing apparatus can perform proper recording andreproducing operations. It is to be noted that an ordinary systemsuffices for providing such conditions.

A recordable area 42 is a region for the user or the like to recordinformation. This recordable area is generally divided into a pluralityof zones 43, and in the same zone, each sector is positioned in adirection of the radius of the disk so that a mirror portion betweensectors is properly formed. FIG. 4(b) shows an arrangement of aplurality of sectors (1, 1+1, 1+2, m, m+1, m+2, . . . ) that arepositioned and formed in the same zone. A specific relation betweenstructure of each sector and information to be recorded will bedescribed later with reference to FIGS. 11(a), 11(b), 12(a), and 12(b).

<Wobbling and Recorded Information>

Structure of recorded information will next be described. Recordedinformation is recorded in an information unit referred to as a sectoron a recording track on the recording medium described above. Generally,information recording is made by using an ECC (Error Correction Code)block as a unit. Also, recorded information is recorded so as to form ablock that includes a plurality of data sectors. One data sector isformed with at least a data address, user data, and ECC. Of course, thedata sector is allowed to have a modified structure that is appropriateto its recording and control method.

FIG. 5(a) shows structure of recorded information in a single sector onthe information recording medium. As described above, each sectorcomprises a recording groove 50 of an appropriate length, and therecording groove is deformed or meanders in a direction intersecting, orfor example perpendicular to an extending direction of the recordinggroove. In the figure, reference numerals 51 and 51′ denote wobbling.Also, a mirror portion 52 is formed at the head portion of each sector.

FIG. 5(a) shows structure of recorded information in a sector (n). FIG.5(b) shows strength of a sum signal when the recorded information isread, while FIG. 5(c) shows strength of a difference signal. In order tofacilitate understanding, the sum signal and the difference signal aredrawn so as to correspond to positions in the sectors of FIG. 5(a). Thesum signal and the difference signal represent a sum of and a differencebetween the signals of wobbling 51 and 51′, respectively. Therefore, inthis case, at the mirror portion 52, the sum signal is at the maximumand the difference signal is zero.

The deformation or wobbling may generally be divided into three regionswithin a single sector. One region is a Header Address Field(abbreviated to HAF), another region is a Sector Address Field(abbreviated to SAF), and the other region is a Wobble Synchronous Field(abbreviated to WSF) Generally, wobbling is subjected to modulation inthe HAF and the SAF, while it has a single frequency in the WSF. Therecording groove meanders in a different manner in each of the regions.Specifically, in logical terms, the method of modulation of addressinformation is different in each of the regions. A specific example ofthe plurality of modulation methods will be described later in detailwith reference to FIGS. 6 to 9.

Such a recording groove is irradiated with a laser spot, the recordinggroove is tracked, and the laser spot scans the recording groove in adirection parallel to the recording groove, whereby a sum signal isobtained from a photodetector that detects a total amount of reflectedlight. The sum signal level transiently rises at the head portion of asector, but its amount of light varies little within the sector becausethe recording groove wobbles only weakly. When the photodetector isdivided in a direction parallel to the recording groove and a resultingdifferential signal is observed, the level of the differential signalbecomes zero at the head portion of a sector, but otherwise a signalindicating the wobbling of the recording groove is obtained throughoutthe sector. Thus, it is possible to find the head of the sector by usingthe sum signal and determine how the recording groove meanders by usingthe differential signal. This will be understood by referring to FIGS.5(a), 5(b), and 5(c). Incidentally, the differential signal is at a zerolevel at the mirror portion 52.

<Examples of Wobbling or Deformation of Recording Groove>

Two methods of wobbling a recording groove will be described withreference to FIGS. 6 to 9. Address information is provided to arecording groove in advance by using these modulation methods. Themethods of providing such address information are illustrated in thefollowing.

According to a first aspect of the present invention, there is provideda method characterized in that the wobbling or deformation of arecording track has a plurality of periods, and thereby addressinformation is recorded by using a plurality of period widths includingat least a first period width and a second period width.

According to a second aspect of the present invention, there is provideda method characterized in that the wobbling or deformation of arecording track has a plurality of periods and has at least a firstregion with a first period width and a second region having at least asecond period width and a third period width, and thereby addressinformation is recorded by using a plurality of regions comprising thefirst region and the second region.

In addition, the following method is useful in concrete, practicalapplications. Specifically, according to a third aspect of the presentinvention, there is provided a method as set forth in the first aspect,characterized in that address information recorded by using a pluralityof period widths including at least the first period width and thesecond period width is sector address information of the recordingmedium.

According to a fourth aspect of the present invention, there is provideda method as set forth in the second aspect, characterized in thataddress information recorded by using a plurality of regions comprisingat least the first region having the first period width and the secondregion having at least the second period width and the third periodwidth is block address information of the recording medium.

These aspects will be described in the following based on concreteexamples. FIG. 6 shows an example of wobbling of a recording groove. InFIG. 6, the axis of ordinates denotes differential signal strength, andthe axis of abscissas denotes a direction of travel in a sector in theform of time. The differential signal described with reference to FIGS.5(a), 5(b), and 5(c) is used, and periods of the differential signal areset to be t1, t2, t3 . . . , t8. In this case, for example, the regionsof t1, t2, t4, and t8 have a short period, while the regions of t3, t5,t6, and t7 have a long period. The wobbling of the recording groove isadjusted in such a manner that these periods represent tS or tL in ahistogram in which the axis of abscissas denotes period and the axis ofordinates denotes frequency. By defining the periods tS and tL of thewobbling of the recording groove as a signal “one” and a signal “zero”(or vice versa), it is possible to record information in the periods ofthe wobbling of the recording groove. FIG. 7 shows an example of thehistogram, in which the axis of abscissas denotes period and the axis ofordinates denotes frequency.

The method of recording information in the recording groove as describedabove is used in the HAF shown in FIG. 5(a). Information in the HAFindicates a sector address of the sector.

FIG. 8 shows another example of wobbling of a recording groove 50. As inFIG. 5(a), reference numerals 51 and 51′ denote wobbling. Also in thiscase, a state of the wobbling is detected by using a differential signalas described with reference to FIG. 5(c). The recording groove 50 isdivided into appropriately small sections b1, b2, b3, . . . , b5. Bydefining unvaried periods of the wobbling of the recording groove withinsuch a small section as a signal “zero” and varying periods of thewobbling of the recording groove within a small section as a signal“one,” it is possible to record information in the periods of thewobbling of the recording groove. Of course, the signals “one” and“zero” may be defined vice versa. FIGS. 9(a) and 9(b) each show anexample of a state detected on the basis of the periods of the wobbling.In the figures, the axis of abscissas denotes period and the axis ofordinates denotes frequency. An example of wobbling that indicates afrequency in FIG. 9(a) has a single period of W2. This state is referredto as a state “zero,” for example. An example of wobbling that indicatesa frequency in FIG. 9(b) has two periods of W1 and W3. This state isreferred to as a state “one,” for example. It is to be noted that whenthe signals “one” and “zero” are defined vice versa, the state “one” andthe state “zero” of wobbling are of course described vice versa. Themethod of recording information in the recording groove as describedabove is used in the SAF shown in FIG. 5(a). Information in the SAFindicates a block address of a block that includes the sector. Thesector address is a so-called integrated address, and therefore can bereproduced relatively easily. On the other hand, the block address is aso-called distributed address. Therefore, its address information isreproduced by using the entire block. A method of reproducing the blockaddress will next be described.

FIGS. 10(a) and 10(b) are diagrams of assistance in explaining a datastructure for block address reproduction. FIG. 10(a) is a diagramshowing a relation between the block and sectors. The figureschematically shows a recording groove 50, wobbling 51, and wobbling51′. FIG. 10(b) illustrates block start bits and block address dataincluded in SAFs. It is to be noted that information shown in the SAFsis only that for block address reproduction. Each part drawn in FIG.10(b) corresponds to one of the SAFs in FIG. 10(a).

The section of a block A in this example contains m sectors. Physicaladdresses of the sectors are set to be n, n+1, . . . , n+m−1,respectively. Also, SAFs of the sectors are set to be SAF(0), SAF(1),SAF(2), . . . , respectively. Each of the SAFs includes information forthe start of block address information (block start bits) and blockaddress data. By obtaining block address data of all the SAFs, thepresent system reproduces a block address of the block A. Morespecifically, in the case of the example shown in FIGS. 10(a) and 10(b),the system obtains all data comprising block address data (0), blockaddress data (1), . . . , block address data (m−1), and then reproducesthe block address of the block A. This is indicated by a “block address”in FIG. 10(b).

The following is a comparison of features of the recording groovewobbling methods of FIG. 6 and FIG. 8 for recording address information.According to the wobbling method of FIG. 6, the frequency of each of theplurality of periods is detected, and at the same time, the frequency ofeach of the plurality of periods is controlled to a specified value.According to the wobbling method of FIG. 8, whether a given section ofthe recording groove has unvaried periods or whether the given sectionhas a plurality of varying periods is detected and the periods arecontrolled.

In a case where periods are changed in a manner shown in FIG. 6, a largeamount of information can be recorded by using a small amount ofwobbles, but error tends to occur in address information when thewobbling or the like of the recording groove is physically deformed byrewriting information many times. On the other hand, in a case whereperiods are changed in a manner shown in FIG. 8, recording of the sameamount of information requires a larger amount of wobbles, but becauseof a high level of redundancy of information recording, error in addressinformation is less likely to occur even when the wobbling of therecording groove is physically deformed by rewriting information manytimes.

<Provision of Record Marks in Recording Groove>

Next, two methods of providing record marks in a recording groove willbe described with reference to FIGS. 11(a), 11(b), 12(a), and 12(b).FIGS. 11(a) and 11(b) are diagrams of assistance in explaining apositional relation between a recording groove and record marks. FIG.11(a) schematically shows a positional relation between a recordinggroove and record marks. FIG. 11(b) illustrates a data structure withina sector. For example, record marks 40 are formed in a sector at asector address (n). These record marks are formed by using regions ofHAF, SAF, and WSF in the sector as desired, whereby information isrecorded. Information to be recorded includes an information dataaddress, user data, and error correction code (abbreviated to ECC)mentioned above, for example.

When information is recorded in such a manner, an error in addressinformation in the HAF tends to occur at a relative early stage due tooverwriting or the like. On the other hand, an error in addressinformation in the SAF due to overwriting is less likely to occurbecause of a high level of redundancy of address information recording.Hence, in the case of the record mark layout of FIG. 11(a), it isdesirable to access an arbitrary sector by using block addressinformation in SAF, where errors are less likely to occur.

Thus, it is possible to form record marks continuously without impairingcontinuity of record marks between sectors. It is therefore possible toform record marks that are reproducible even with a simple reproducingsystem. Incidentally, information indicating that extraction of addressinformation from the sector is to be carried out in SAF may be recordedwithin the data address.

FIGS. 12(a) and 12(b) are diagrams of assistance in explaining apositional relation between a recording groove and record marks, whichrelation is different from that of FIGS. 11(a) and 11(b).

Record marks 40 are formed in a sector at a sector address (n). Theserecord marks are formed by using regions of SAF and WSF in the sector,whereby information is recorded. In this case, no information isrecorded in an HAF section. Sector data to be recorded includes suchinformation as an information data address, a guard buffer VFO situatedbefore the information data address, user data, error correction code(abbreviated to ECC), and a guard buffer in the last section.

This sector data structure has the same significance as in a DVD-RAM.Since information is not recorded in the HAF section, information in theHAF is correctly reproduced at all times even if record marks arerewritten many times. By recording the address of the sector in the HAF,it is possible to obtain the physical address of the sector prior touser data at all times. Therefore, accessibility to data at a givenposition is improved, and thereby random access capability is enhanced.Also, since the sector data structure is the same as that in a DVD-RAM,overwrite characteristics are improved. However, since record marks areformed intermittently between sectors, continuous record markreproduction requires an appropriate timing circuit. Incidentally,information indicating that extraction of address information from thesector is to be carried out in the HAF may be recorded within the dataaddress.

While description has been made about sector data, it is essential inthe present invention that address selecting information that specifieswhich of the block address information and the sector addressinformation in a sector should be chosen be recorded within the sectorin the information recording medium. It is also essential that addressselecting information that specifies which of the block addressinformation and the sector address information should be used berecorded in the entire recording area of the disk (the address selectinginformation will be tentatively referred to as entire area addressinformation). Then, on the basis of the address selecting information orthe entire area address selecting information, the address switchingdevice is switched to thereby record and reproduce recording informationin a desired format. In the case of FIGS. 11(a) and 11(b), for example,address selecting information that specifies the use of a block addressis inserted as reference numeral 33 in FIG. 11(b). Similarly, in thecase of FIGS. 12(a) and 12(b), address selecting information thatspecifies the use of a sector address is inserted as reference numeral34 in FIG. 12(b). Either the block address information or the sectoraddress information is selected by using the information of 33 or 34.

Selection of record mark arrangement in a sector as shown in FIG. 11(a)or FIG. 12(a) depends on the recording medium, the system, andrequirements of the user. Technical concepts on which to base suchselection will be illustrated in the following.

(1) When a certain amount of similar user data is to be recorded in thesame sector, the record mark arrangement of FIG. 11(a) allows intervalsbetween record marks to be wider. Therefore, in the case of a simplymade recording medium with a relatively high level of noise, a recordmark specifying that the record mark arrangement of FIG. 11(a) be madeover an appropriate area of the recording medium is created, and thusthe record mark arrangement of FIG. 11(a) is used at all times.

(2) When high random access characteristics in particular are requiredof the system, it is desirable to use HAF in FIG. 12(a). Thus, therecord mark arrangement of FIG. 12(a) is used to meet requirements ofthe system or the user.

(3) When high overwrite characteristics in particular are required ofthe system, it is desirable to use HAF in FIG. 12(a). Thus, the recordmark arrangement of FIG. 12(a) is used to meet requirements of thesystem or the user.

(4) When importance is attached to reproduction compatibility with asimply constructed reproducing apparatus that can play back only arecording medium having continuous record marks, the record markarrangement of FIG. 11(a) is used to meet requirements of the system orthe user.

By selecting such recording film arrangements in various othersituations as appropriate, information recording suitable for thepurpose and with high compatibility can be made with reliability.

As described above, the recording medium according to the presentinvention allows information recording having high compatibility with aplurality of recording methods to be made with reliability. This meansthat the present invention allows a DVD-RW format and a DVD-RAM formatto be used in a single recording medium.

A specific example of an information recording and reproducing apparatusaccording to the present invention will next be described. This examplecan be summarized as follows. Specifically, an information recording andreproducing apparatus which records information by irradiating arecording track on a recording medium with an energy beam and therebyforming a record mark, and is capable of accessing a recording mediumprovided in advance with a recording track that has wobbling ordeformation with a predetermined period comprises a wobble signaldetecting circuit for converting the period of the wobbling or thedeformation of the recording track into an electric signal; a blockaddress detecting circuit for detecting a block address on the basis ofa period of the signal representing the wobbling or the deformation ofthe recording track obtained by the wobble signal detecting circuit; asector address detecting circuit for detecting a sector address on thebasis of the period of the signal representing the wobbling or thedeformation of the recording track obtained by the wobble signaldetecting circuit; and an address switching circuit for switchingbetween output of the block address detecting circuit and output of thesector address detecting circuit and thereby transmitting a resultingoutput to a controller.

FIG. 13 is a block diagram of an information recording and reproducingapparatus according to an embodiment of the present invention. For thepurpose of description, FIG. 13 shows a state in which a recordingmedium 100 is inserted into the information recording and reproducingapparatus. Although the recording medium 100 is essential forinformation recording and reproduction, the recording medium 100 isextracted from or inserted into the recording and reproducing apparatusas required.

An example of an information recording and reproducing apparatus willhereinafter be described with reference to FIG. 13. The informationrecording and reproducing apparatus essentially has a mechanism formoving an information recording medium, an optical system forirradiating the recording medium with light, and an electric system fordriving the mechanism and the optical system. The optical system ismostly housed in a case 117, and a moving mechanism supporting the caseallows the recording medium to be irradiated with light in a desiredmanner.

As a fundamental configuration for information recording andreproduction, the recording and reproducing apparatus has an energy beamgenerator, a power adjusting mechanism for adjusting a power level of anenergy beam generated by the energy beam generator, a holding mechanismcapable of holding the recording medium, a moving mechanism forirradiating the recording medium with the energy beam and moving theenergy beam relatively to the recording medium, and a detector fordetecting the energy beam reflected or transmitted in the informationrecording and reproducing apparatus.

First, the section of the mechanism for moving the recording medium willbe described. A motor 110 is attached to a casing 108, and a chuckingmechanism 112 is attached to a rotation spindle 111 of the motor 110.The chucking mechanism 112 holds the recording medium 100. Therefore,the chucking mechanism 112 serves as a mechanism for holding therecording medium 100. The motor 110, the rotation spindle 111, and thechucking mechanism 112 form a moving mechanism for moving the recordingmedium 100 and the energy beam relatively to each other.

A rail 115 is attached to the casing 108. A rail guide 116 guided by therail 115 is attached to the case 117. A linear gear 119 is attached tothe case 117, and a rotary gear 120 is attached to the linear gear 119.The case 117 is moved linearly along the rail 115 by transmittingrotation of a rotary motor 118 attached to the casing 108 to the rotarygear 120. The direction of the linear motion of the case 117 issubstantially the direction of the radius of the recording medium 100.

The optical system will next be described. A magnet 121 is attached tothe case 117 housing the optical system. Also, an objective lens 136 isattached to the case 117 in a direction substantially normal to therecording surface of the recording medium 100. The objective lens 136 isattached to the case 117 via a suspension 123 that is capable of movingsubstantially in only two directions of the radius of the recordingmedium 100. Also, a coil 122 is attached to the objective lens 136 so asto be substantially opposed to the magnet 121. Effects of magnetic forceresulting from a current flowing through the coil 122 allow theobjective lens 136 to move in two directions, that is, a directionsubstantially normal to the recording surface of the recording medium100 and substantially a direction of the radius of the recording medium100. The rail 115, the rail guide 116, the case 117, the magnet 121, thesuspension 123, the coil 122, and the objective lens 136 form apositioning mechanism for positioning the energy beam at a specifiedposition on the recording medium 100.

A semiconductor laser 131 serving as the energy beam generator isattached to the case 117. The energy beam emitted from the semiconductorlaser 131 passes through a collimating lens 132, a beam splitter 133,and then the objective lens 136. Part of the light emitted from theobjective lens 136 is reflected by the recording medium 100, passedthrough the objective lens 136, reflected by the beam splitter 133, andcollected by a detecting lens 134, whereby intensity of the resultinglight is detected by a photodetector 135. A light receiving area of thephotodetector 135 is divided into a plurality of areas. Light intensitydetected in each of the light receiving areas is amplified by anamplifier 152 and also subjected to arithmetic operation, wherebyinformation on positional relation between a light spot collected by theobjective lens 136 and the recording medium 100 (servo signal) and aninformation read signal are detected. The servo signal is sent to aservo controller 151. The read signal is sent to a decoder 153 via aslicer 170 for converting the signal into binary code and a phase lockloop (abbreviated to PLL) circuit 173.

Fundamental operation of the information recording and reproducingapparatus will next be described. The recording medium 100 is mounted inthe information recording and reproducing apparatus, and the chuckingmechanism 112 secures the recording medium 100. A detector 140 isactivated by securing the recording medium 100, and then a resultingsignal is sent to a system controller 150. In response to the signal,the system controller 150 controls the motor 110 so as to rotate therecording medium 100 at an appropriate rotation speed. The systemcontroller 150 also controls the rotary motor 118 to position the case117 to an appropriate position.

In addition, the system controller 150 effects control so as to emitlight from the semiconductor laser 131, operate the rotary motor 118 byoperating the servo controller 151, and position a focal spot formed bythe objective lens 136 at a specified position on the recording medium100 by passing a current through the coil 122. The servo controller 151sends to the system controller 150 a signal indicating that the focalspot is formed on the recording medium 100. The system controller 150gives the decoder 153 an instruction to decode a read signal. When atrack being read is not an information track of a control data zone, thesystem controller 150 instructs the servo controller 151 to position thefocal spot on the information track of the control data zone. As aresult of the above operations, the system controller 150 reads aninformation track in a read-in area, thus reading information onrecording and reproduction of the medium.

When an instruction to write information or information to be written issent from a host controller to the system controller 150 via an inputconnector 159, the system controller 150 instructs the servo controller151 to position the focal spot on an appropriate track on the recordingmedium 100.

A signal obtained at the photodetector 135 is amplified by the amplifier152, and then sent to a wobble detecting circuit 171. A recording trackis provided with desired wobbling or deformation, and the wobbledetecting circuit 171 detects the period of the wobbling or thedeformation. The wobbling or the deformation of the recording track isprovided according to the techniques described with reference to FIGS. 1to 7.

A period signal obtained by the detection of the wobble detectingcircuit 171 is subjected to frequency (period) conversion by a frequencyconverting circuit 172 to be used as a clock for recording andreproduction. A conversion factor of the frequency converting circuit172 is adjusted according to whether the record mark arrangement of FIG.5(a) or the record mark arrangement of FIG. 6 is used.

The signal from the wobble detecting circuit is sent to a block addressdetecting circuit 180 and a sector address detecting circuit 181,whereby each of the circuits provides an address signal. An addressswitching circuit 182 chooses one from the address signals of thecircuits, which depends on sector structure information included in adata address. Alternatively, the user or the system forcefully choosesone from the address signals. According to selected address information,the focal spot is positioned to a given sector on the recording medium100.

Information to be written goes through a signal processing circuit 161to be converted into an NRZI signal. The signal converted into the NRZIsignal is sent to a pattern generating circuit 155. According to amethod of record mark arrangement within a sector specified by thesystem controller 150, the pattern generating circuit 155 makes (1) apattern of an area of user data to be recorded within the sector, (2) arecord mark arrangement to be attached before the user data area (bufferand other fields), (3) a record mark arrangement to be attached afterthe user data area (buffer and other fields), and the like. The patterngenerating circuit 155 thereby completes a row of patterns of recordmark arrangement within the sector. A sector data structure as shown inFIG. 11(b) or FIG. 12(b) is completed according to the record markarrangement of FIG. 11(a) or the record mark arrangement of FIG. 12(a),respectively.

The pattern generating circuit 155 is supplied with the fundamentalclock for recording and reproduction generated by the frequencyconverting circuit 172. The pattern generating circuit 155 sequentiallysends individual recording patterns that it created to a laser drivercircuit 154 in synchronism with the recording and reproducing clock. Thelaser driver circuit 154 generates a writing pulse according to a recordmark pattern to be written that is sent from the pattern generatingcircuit 155 and in synchronism with the recording and reproducingfundamental clock generated by the frequency converting circuit 172. Thewriting pulse is sent to the semiconductor laser 131 to thereby drivethe semiconductor laser 131. The semiconductor laser 131 thereby emitslight, and an amount of emission energy of the semiconductor laser 131is temporally modulated according to the information to be written. Theemitted light is applied through the collimating lens 132 and theobjective lens 136 to the recording medium 100, whereby record marks areformed on the recording medium.

In a case where record marks are formed by using change in the intensityof light applied to the recording medium, as in a DVD-RAM and an opticalmodulation type magneto-optical disk, information to be recordedultimately appears as change in the driving current for thesemiconductor laser 131, and the change in the driving current is insynchronism with the fundamental wave of the recording and reproducingclock. In the case of a magnetic field modulation type magneto-opticaldisk, the driving current for the semiconductor laser 131 is insynchronism with the fundamental wave of the recording and reproducingclock and thus modulated at fixed periods, and the strength anddirection of an external magnetic field applied to a portion of therecording medium are modulated according to the information to berecorded and changed in synchronism with the fundamental wave of therecording and reproducing clock.

In the above example, the wobble period detected by the wobble detectingcircuit 171 is used to generate the fundamental wave of the recordingand reproducing clock. The wobble period detected by the wobbledetecting circuit 171 may be used not only to generate the fundamentalwave of the recording and reproducing clock but also to control therotation speed of the spindle motor 110.

When an instruction to reproduce information is sent from the hostcontroller to the system controller 150 via the input connector 159, thesystem controller 150 instructs the servo controller 151 to position thefocal spot on an appropriate track on the recording medium 100. A signalobtained at the photodetector 135 is amplified by the amplifier 152, andthen sent to the wobble detecting circuit 171 and the slicer 170. Thewobble detecting circuit 171 detects the period of wobbling ordeformation of the recording track. A signal from the wobble detectingcircuit is sent to the block address detecting circuit 180 and thesector address detecting circuit 181, whereby each of the circuitsprovides an address signal. The address switching circuit 182 choosesone from the address signals of the circuits, which depends on sectorstructure information included in a data address. Alternatively, theuser or the system forcefully chooses one from the address signals.According to selected address information, the focal spot is positionedto a given sector on the recording medium 100. The period signalobtained by the detection of the wobble detecting circuit 171 issubjected to frequency (period) conversion by the frequency convertingcircuit 172 to be used as a fundamental wave of a recording andreproducing clock. The conversion factor of the frequency convertingcircuit 172 is changed according to information indicating the type ofdata structure recorded in the data address or the type of datastructure written in control data. The fundamental wave of the recordingand reproducing clock generated by the frequency converting circuit 172is inputted to the PLL circuit 173. The PLL circuit 173 is oscillated byitself at the same frequency as that of the fundamental wave of therecording and reproducing clock. The PLL circuit can adjust a phaserelation between the fundamental wave of the recording and reproducingclock provided by the frequency converting circuit 172 and itsself-oscillating wave, and thus adjusts the phase of theself-oscillating wave to thereby generate a reproducing clock. The phaseof the self-oscillating wave is adjusted in such a way that thereproducing clock is synchronized with a binary reproduction signalobtained by the slicer 170 in a most desirable manner. The reproducingclock and the binary reproduction signal are sent from the PLL circuitto the decoder 153 to decode recorded data, and then read information issent to the host controller via an output connector 158.

In the above example, the wobble detection signal is subjected tofrequency conversion to generate the fundamental wave of the recordingand reproducing clock and to thereby obtain the reproducing clock.However, for reproduction, a method of reproducing a reproducing clockby using only a reproduction signal of recorded data instead of usingthe wobble detection signal is also conceivable. In addition, the wobbleperiod detected by the wobble detecting circuit 171 may be used tocontrol the rotation speed of the spindle motor 110.

Incidentally, power is supplied to the system controller and other partsvia a terminal 160.

Thus, according to the embodiment shown in FIG. 13, the number ofchannel bits within a unit sector is made variable and changed asrequired, and thereby it is possible to realize a recording andreproducing apparatus that can adapt different record mark arrangementswithin sectors to a recording medium in a single format. It is thereforepossible to construct an information recording apparatus that canreliably record information at all times.

The information recording method or the information recording apparatusfor recording information on a recording medium by energy irradiationrenders sector data structure within a sector variable, and allowsselection between a data structure using a sector address and a datastructure using a block address.

According to the present invention, it is possible to suitably andselectively choose a method of arranging record marks within a sector ona disk in a single substrate format. This makes it possible to produce arecording medium suited for a purpose more readily and to increasecompatibility between pieces of recorded information written by aplurality of methods of record mark arrangement. Thus, it is possible toreadily record and reproduce data with high reliability.

The recording medium and the recording and reproducing method accordingto the present invention make it possible to select a plurality ofaddress data detections and data structures on a disk in a singlephysical format depending on the purpose. In addition, the recording andreproducing apparatus according to the present invention makes itpossible to simply and readily perform recording and reproduction by aplurality of address systems employed in a disk.

In order to facilitate understanding of the drawings, main referencenumerals are listed in the following.

100 . . . recording medium, 108 . . . casing, 110 . . . motor, 111 . . .rotation spindle, 112 . . . chucking mechanism, 115 . . . rail, 116 . .. rail guide, 117 . . . case, 118 . . . rotary motor, 119 . . . lineargear, 120 . . . rotary gear, 121 . . . magnet, 122 . . . coil, 123 . . .suspension, 131 . . . semiconductor laser, 132 . . . collimating lens,133 . . . beam splitter, 134 . . . detecting lens, 135 . . .photodetector, 136 . . . objective lens, 140 . . . detector, 150 . . .system controller, 151 . . . servo controller, 152 . . . amplifier, 153. . . decoder, 154 . . . laser driver circuit, 155 . . . patterngenerating circuit, 158 . . . output connector, 159 . . . inputconnector, 161 . . . signal processing circuit, 170 . . . slicer, 171 .. . wobble detecting circuit, 172 . . . frequency converting circuit,173 . . . PLL circuit, 180 . . . block address detecting circuit, 181 .. . sector address detecting circuit, and 182 . . . address switchingcircuit.

What is claimed is:
 1. An information recording and reproducingapparatus comprising: a signal detecting circuit for converting a periodof a configuration of each record retaining portion on a recording trackinto an electric signal, said recording track being provided in advanceon a recording medium and including said record retaining portion havingthe configuration with the predetermined period; first address detectingcircuit for detecting a first address by converting the period of theelectric signal obtained by said signal detecting circuit; secondaddress detecting circuit for detecting a second address by convertingthe period of the electric signal obtained by said signal detectingcircuit, said first address being formed in a first recording unit of afirst length, and the second address being formed in a second recordingunit of a second length that is shorter than the first length; and anaddress switching circuit for switching between said first addressdetecting circuit and said second address detecting circuit.
 2. Aninformation recording and reproducing apparatus according to claim 1,wherein said first address is a block address and said second address isa sector address.
 3. An information recording and reproducing apparatusaccording to claim 1, wherein said address switching circuit is adaptedto switch between an output of said first address detecting circuit andan output of said second sector address detecting circuit, and totransmit a resulting output to a controller.
 4. An information recordingand reproducing apparatus according to claim 1, wherein a modulation ofsaid first address and a modulation of the second address are differentfrom each other.
 5. An information recording and reproducing apparatusaccording to claim 1, wherein a physical form of said first address anda physical form of said second address are different from each other.